Dimmer circuits for lighting are popular and ubiquitous, allowing users to set their lighting to desired levels for various tasks. However, the traditional dimming circuits lack the flexibility to keep up with modern innovation in lighting and electronics. Dimmers designed for incandescent lighting do not work properly on forms of lighting more recently developed for greater energy efficiency, such as direct off-line-driven light-emitting diode (LED) lighting. One reason for this is that these dimmers require 15-25 W to operate which is incompatible with the low power associated with more efficient lighting systems. Existing solutions, such as the traditional triac dimmer, have drawbacks of their own. For instance, because of the forward voltage of series-connected LEDs, conduction only occurs near the peaks of the alternating current (AC) waveform, causing inconsistent and inefficient light output. As a result, operation of LEDs using triac dimmer results in extremely non-linear dimmer operation.
Thus, there remains a need for an efficient dimming control capable of controlling high-efficiency lighting and presenting a linear dimming profile.